logging: log_minimal: Fix violation to rule 14.4
logging: log_minimal: Fix violation to rule 14.4

Non-boolean essential type is being interpreted as a boolean.

Signed-off-by: Flavio Ceolin <979b9165500b0741b9d0500e2efd74fc1547bff7@intel.com>

nashif/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,nashif/zephyr,finikorg/zephyr,nashif/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,nashif/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,nashif/zephyr